Development of a validated method for the simultaneous determination of amphetamine,methamphetamine and methylenedioxyamphetamines (MDA,MDMA, MDEA) in serum by GC-MS after derivatisation with perfluorooctanoyl chloride

A rapid and simple method for the simultaneous detection and quantitation of amphetamine, methamphetamine, methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA) and methylenedioxyethylamphetamine (MDEA) in human serum was developed and fully validated. Serum samples were extracted with cyclohexane, derivatised with perfluorooctanoyl chloride without prior evaporation of the solvent and analysed with gas chromatography-mass spectrometry (GC-MS) in the selected ion monitoring mode (SIM). For quantitation, deuterated analogues were used as the internal standards. The limit of detection (LOD) and lower limit of quantitation (LLOQ), bias and within-day and between-day precision were determined. LODs calculated as the average of the six calibration curves were below 5 ng/mL for all of the measured compounds; LLOQs obtained in the same manner were below 20 ng/mL, with the exception of MDA (24.1 ng/mL). The coefficients of variation were below 7% within series, 10% or less between series and the bias was below 8% for all compounds. The calibration curves were linear between the lower limits of quantitation and 800 ng/mL. Presented in part at 12. Jahrestagung, Deutsche Gesellschaft für Rechtsmedizin, May 2003, Kiel, Germany.     

Rhodium in car exhaust tips by total automatic activation analysis

Exhaust systems of modern cars contain catalysts for the reduction of CO, NO_x and hydrocarbons. These catalysts are made of ceramic materials with a large surface on which platinum metals catalyse the oxidation. The catalysts contain approximately 2 g of platinum and 0.4 g of rhodium. Recently platinum is being replaced by palladium. During driving the platinum-group elements (PGEs) are expelled from the tip in fine particles and are deposited in the environment. For a projected study of emissions from cars driven on streets and highways it is important to know which elements can be measured by short time activation analysis without any chemical procedure.     

Actual state of high-rate digital gamma-spectrometry

Two commercially available digital filters with selectable, fixed time constants and triangular pulse response are discussed to outline their potential advantages over traditional analog filters with semi-Gaussian pulse shape. A solution for the “resolution or throughput rate” dilemma is offered by the preloaded digital filter fulfilling the postulate for the ideal adaptive filter with optimum resolution at any counting rate. Throughput rates of >100 kc/s are demonstrated for the preloded digital filter at resolutions superior to those of fixed shaping time filters.     

Automatic NAA: Saturation activities

A system for Automatic NAA is based on a list of specific saturation activities determined for one irradiation position at a given neutron flux and a single detector geometry. Originally compiled from measurements of standard reference materials, the list may be extended also by the calculation of saturation activities from k ₀ and Q ₀ factors, and f and a values of the irradiation position. A systematic improvement of the SRM approach is currently being performed by pseudo-cyclic activation analysis, to reduce counting errors. From these measurements, the list of saturation activities is recalculated in an automatic procedure.     

Review of loss-free counting in nuclear spectroscopy

This paper is a review of techniques for real-time correction of counting losses in nuclear pulse spectroscopy which became known under the name of loss-free counting (LFC).     

Dark-matter search with CRESST

The CRESST experiment is looking for non-baryonic particle dark matter via nuclear scattering in CaWO₄. The simultaneous measurement of the heat and the scintillation light generated by an event in a CaWO₄ single crystal is used to discriminate between electron and nuclear recoils thanks to their different light output. This allows an efficient suppression of the electron recoil background. The set-up consists of modules with a 300 g CaWO₄ crystal mounted in a reflective housing together with a light detector. The heat signal is read out using a superconducting transition-edge sensor (TES) made of tungsten evaporated directly on to the crystal that is operated at a few mK. Currently the second phase of the experiment is being set up at the Laboratori Nazionali del Gran Sasso in which it is planned to run 33 detector modules providing a total target mass of 10 kg. First test runs with prototype detectors have been successfully performed. Presented by W. Westphal at the Workshop on calculation of double-beta-decay matrix elements (MEDEX’05), Corfu, Greece, September 26–29, 2005.     

A Mössbauer spectroscopic study of salt lake sediments from Qaidam basin

Mössbauer spectroscopy, X-ray diffractometry and chemical fractionation have been used to study the clay smaples in sediments of Charhan playa and Qinghai lake. The spectral components of the Mossbauer spectra of the samples are attributed to Fe²⁺ ions in chlorite and siderite, Fe³⁺ ions in clay minerals and hematite, and partly in amorphous ferric hydroxides. The essential difference in the mineral composition of the sediments of both lakes is the presence of siderite in the samples of Char han playa, whereas it is absent in the samples of Qinghai lake. The fraction of the amorphous ferric hydroxides is higher in the sediments of Qinghai lake. Total Fe²⁺/Fe³⁺ ratios increase with sediment depth of Charhan playa, whereas these ratios are altogether smaller and run through a maximum at a certain depth for Qinghai lake.